Filtering Explicit Content

Many web sites provide a setting to reduce the amount of explicit, or objectionable, content returned by the site. The user configures these settings, but many users are unaware such a setting exists, or that it needs to be set for each web site. Additionally, the security administrator cannot audit that users have configured the setting. As a result, users can be exposed to objectionable content or can inadvertently trigger filtering of objectionable content on the Cisco security service (Cisco WSA or CWS), sometimes causing uncomfortable questions from human resources or from management.

An emerging standard defines a new HTTP header, “Prefer: Safe,” which does not require the user to configure each web site. This feature is implemented by Firefox, Internet Explorer 10, and Bing. We anticipate more clients and more content providers will support this emerging standard.

Both Cisco Web Security Appliance (WSA) and Cloud Web Security (CWS) support this emerging standard, and can be configured to insert this header on behalf of HTTP and HTTPS clients. In this way, the security administrator can cause all traffic to default to avoiding explicit or objectionable content, without relying on users to configure their browser or to configure each visited web site.